fix: add mutex to prevent concurrent map writes in Docker agent CPU tracking

The agent was crashing with 'fatal error: concurrent map writes' when
handleCheckUpdatesCommand spawned a goroutine that called collectOnce
concurrently with the main collection loop. Both code paths access
a.prevContainerCPU without synchronization.

Added a.cpuMu mutex to protect all accesses to prevContainerCPU in:
- pruneStaleCPUSamples()
- collectContainer() delete operation
- calculateContainerCPUPercent()

Related to #1063

analyze_coverage.py

@@ -0,0 +1,56 @@
+
+import sys
+import os
+
+def parse_coverage(filename):
+    if not os.path.exists(filename):
+        print(f"File {filename} not found")
+        return
+
+    package_stmts = {}
+    package_covered = {}
+
+    with open(filename, 'r') as f:
+        lines = f.readlines()
+
+    current_mode = ""
+    for line in lines:
+        if line.startswith("mode:"):
+            current_mode = line.split()[1]
+            continue
+        
+        parts = line.strip().split(':')
+        if len(parts) != 2:
+            continue
+        
+        file_path = parts[0]
+        # Package is directory of file_path
+        package_name = os.path.dirname(file_path)
+        
+        metrics = parts[1].split()
+        if len(metrics) != 3:
+            continue
+            
+        # start_end = metrics[0]
+        num_stmts = int(metrics[1])
+        count = int(metrics[2])
+        
+        package_stmts[package_name] = package_stmts.get(package_name, 0) + num_stmts
+        if count > 0:
+            package_covered[package_name] = package_covered.get(package_name, 0) + num_stmts
+
+    results = []
+    for pkg, total in package_stmts.items():
+        covered = package_covered.get(pkg, 0)
+        percent = (covered / total) * 100 if total > 0 else 0
+        results.append((pkg, percent, covered, total))
+
+    # Sort by percentage (ascending)
+    results.sort(key=lambda x: x[1])
+
+    print("Package Coverage Report (Bottom 20):")
+    for pkg, pct, cov, tot in results[:20]:
+        print(f"{pct:6.2f}% ({cov}/{tot}) {pkg}")
+
+if __name__ == "__main__":
+    parse_coverage("coverage.out")